The present invention relates to an apparatus for subjecting a target object to a plasma process in a semiconductor processing system by using a plasma and, more particularly, to an inductively coupled type dry etching apparatus. The term "semiconductor processing" used herein includes various kinds of processes which are performed to manufacture a semiconductor device or a structure having wiring layers, electrodes, and the like to be connected to a semiconductor device, on a target substrate, such as a semiconductor wafer or an LCD substrate, by forming semiconductor layers, insulating layers, and conductive layers in predetermined patterns on the target substrate.
As a plasma processing apparatus used in semiconductor processing systems, there is an inductively coupled type dry etching apparatus. This dry etching apparatus generally has a process chamber with a ceiling of a dielectric wall, on which an annular or spiral RF (radio-frequency) antenna is disposed.
The dielectric wall has an inner surface exposed to the interior atmosphere of the process chamber, and by-products derived from radicals in a plasma tend to adhere to the exposed inner surface during a plasma process. By-products adhering to the exposed inner surface increase the dielectric constant of the exposed inner surface, thereby lowering energy efficiency. Further, the amount of radicals present in the process chamber varies at every process, depending on the amount of by-products adhering to the exposed inner surface, thereby causing the process to be unreliable. As a result, problems arise in that the throughput of the process is decreased and the planar uniformity of the process is deteriorated. Accordingly, it is preferable to minimize the amount of by-products adhering to the exposed inner surface of the dielectric wall in the inductively coupled type plasma processing apparatus.
Jpn. Pat. Appln. KOKAI Publication No. 8-144072 discloses an inductively coupled type plasma processing apparatus in which a resistance heating body is embedded in a dielectric wall. Generally, if a surface exposed to a plasma is kept at a high temperature, the adhering coefficient of by-products relative to the surface becomes low. Accordingly, the dielectric wall is kept at a high temperature by the resistance heating body, so that the exposed surface of the dielectric wall is prevented from being stained with by-products.
However, the resistance heating body embedded in the dielectric wall requires a complicated structure of the dielectric wall. Further, it is necessary for the resistance heating body to be provided with a power supply, an attachment for the power supply, a controller, and the like. These members cause the initial cost of the entire apparatus to be higher. Furthermore, since the coefficient of thermal expansion of the dielectric wall differs from that of the resistance heating body, cracks may be generated in the dielectric wall due to repeated thermal expansion and contraction over a long period of time.